Track and follower



Nov. 5, 1963 c. E. VANDENBERG 3,109,386

TRACK AND FOLLOWER Filed May 13, 1957 4 Sheets-Sheet 1 2 4 Owlb 750FIG.3

INVENTOR. CORNELIUS E. VANDENBERG BY aim 5.

ATTORNEY Nov. 5, 1963 c. E. VANDENBERG TRACK AND FOLLOWER 4 Sheets-Sheet2 Filed May 15, 1957 (-2-) ASSUMED INVENTOR. CORNELIUS E. VANDENBERGATTORNEY 1963 c. E. VANDENBE RG 3,109,336

TRACK AND FOLLOWER Filed May 13, 1957 4 Sheets-Sheet 3 INVENTOR.CORNELIUS E. VANDENBERG ATTORNEY 1963 c. E. VANDENBERG 3,109,336

TRACK AND FOLLOWER Filed May 15, 1957 4 Sheets-Sheet 4 INVENTOR.CORNELIUS E. VANDENBERG BY YL s. WMQWLM ATTORNEY United States Patent3,339,386 TRAQK AND F0116 WEEK Cornelius E. Vandenherg, Fullerton,Qalili, assigncr to North American Aviation, Filed May 13, 1957, Ser.No. 653,884 13 Claims. (tCl. ice-r34) This invention is directed to anew aerodynamic bearing utilizing the inherent stability of anaerodynamically shaped body when moved supersonically relative toadjacent guide walls to support that body out of contact with the walls.

Heretofore when a supersonically movable body was to be guided and/orsupported by a stationary guide means, it had been thought necessary tomaintain physical contact between these parts. This has been done with aresultant fritional penalty. Rollers operating on guide rails or cables,skids sliding on guide rails, and balls or rollers in bearings rollingwith respect to their races, all serve to illustrate the fields in whichsuch frictional penalties are encountered and in which the presentinvention may be utilized to substantially eliminate these penalties.

The term aerodynamic shape, as used herein, is defined as a shape whichhas been designed to produce a desirable low dag (as a stream-linedshape), a desirable ratio of lift-to-drag and desirable pitch, roll andyaw moment characteristics for the operating conditions in the fluidmedium considered. The term fluid medium, as used herein, is meant toinclude but not to be restricted to a fiuid such as air, nor is anyrestriction to be placed upon the compressibility of the fluid.

The basic tenet of this invention represents that if an aerodynamicshape be moved supersonically through a fluid media and adjacently ofproperly constructed guide surfaces or tracks, that shape will beaerodynamically supported out of physical contact with the guidesurfaces. The aerodynamic shape, which may be called a track follower,may then be said to float relative to the guide surfaces. The followerand the guide surfaces thus cooperate to form a new type of low frictionbearing. This hearing may be utilized to replace the above-mentionedrollers operating on guide rails, skids sliding on guide rails, or inmany instances, to replace ball or roller bearlugs and thussubstantially eliminate a source of considerable mechanical difiiculty,i.e., friction.

it is therefore an object of this invention to provide a new andimproved bearing design.

It is a further object of this invention to provide an aerodynamicbearing which will substantially eliminate friction between relativelymoving parts.

A still further object is to provide guide means cooperating withairfoil means for the aerodynamic support of a structural load.

Yet another object is to provide a means of support for a movablestructural load while eliminating the nece sity of physical contactbetween the load and its support means.

Another object is to provide a constant level track and followerassembly being operable over wide track tolerance ranges.

Still another object of this invention is to enable a vehicle to beguided and supported during supersonic operation without paying unduefrictional penalties.

Other objects of invention will become apparent from the followingdescription taken in connection with the accompanying drawings, inwhich:

FIG. 1 is a schematic of a two-dimensional aerody namic shape centrallylocated between two guide walls and illustrating the principle of thisinvention;

FIG. 2 is a schematic further describing the inventive E y l fi gPatented Nov. 5, l 963 64 principle and showing the aerodynamic shapemoved off center between the guide walls;

H8. 3 is a schematic illustrating the meanings of symbols as used in theFIG. 4 graph;

FIG. 4 is a graph comparing operation speed to the ratio of passagewidth to follower chord;

FIG. 5 is a cross sectional view of a bearing configuration utilizingthe principle of this invention;

FIG. 6 is a perspective cutaway view of a vehicle support utilizing anogival follower and a tubular wall;

FIG. 7 is a perspective view of the invention utilizing fluid-filledtroughs;

FIG. 8 shows a follower surrounding a conventional railroad rail andhaving a standard slipper arrangement;

FIG. 9 is an end elevational view illustrating variations in a multipletrack and follower arrangement for the support of a vehicle.

In order that a thorough understanding of the principles of thisinvention might be had, a two-dimensional track follower of diamondairfoil shape situated between two walls or guide surfaces and immersedin a supersonically moving fluid stream is first considered. Because theeffect of the airfoil is the same whether the air flows past astationary airfoil or the airfoil moves through a stationary fluid mass,for convenience the former will be considered, as represented in H0. 1and HG. 2. The symbols as used therein and throughout this specificationare defined as follows:

D the distance from the airfoil leading edge to the lower wall;

D the distance from the airfoil to the wall at its throat;

M=Mach number=the ratio of the velocity of the fluid medium relative tothe wall at a particular point in the stream to the velocity of sound atthat point in the stream;

M =Free stream Mach number approaching the leading edge of the airfoil;

M =Free stream Mach number leaving the trailing edge of the airfoil;

6 =Half angle of the airfoil;

A =The amount of airfoil displacement toward the Wall.

The presence, in PEG. 1, of an airfoil 1 between upper wall 2 and lowerwall 3 presents a converging duct section 4 to an incoming supersonicairstream. The air stream flowing past the lower surface In of airfoil l issubject to a contraction ratio of D /D If this ratio is less than thatrequired to decelerate the flow to M :1 at the throat 5 (including thedeceleration effects of reflected shocks off the duct walls and theeffects of boundary layer buildup) and the airfoil half-angle 19,, isless than critical for the flow conditions and airfoil angle of attack,an oblique shoclc ti will be maintained at the airfoil lead ing edge.The pressure increase along lower surface la will be a function of theoblique shock pattern 6 tain M :1 at throat 5, choking of the flowobtains, and

an oblique shock can no longer be maintained at the airfoil leadingedge. A normal bow shock 7 is then formed ahead of lower surface in,allowing spill-over past the upper surface 1b to occur. The pressuresnow acting along the lower surface to correspond to those following anormal shock, and are considerably higher than before. Further movementof airfoil 1 toward wall 3 will give an increased contraction ratio, astronger normal shock '7 moved up-stream in the duct, and morespill-over past upper surface lb. Static pressures along the lowersurfaces will be slightly increased in spite of decreased stagnationpressures in that area resulting from increased shock intensity, thehigher static pressures being required to provide for the increasedspill-over flow.

At upper surfaces lb, movement of airfoil 1 toward the lower walls 3results in a decreased contraction ratio, a higher Mach number at throat5a and a slightly lowered pressure recovery along upper surfaces lib.When spillover from surface la is obtained, the oblique shockoriginating at the leading edge of the airfoil becomes detachedforwardly of the leading edge to provide sufficient volume toaccommodate the spill-over mass flow. The shock wave is displacedforwardly, curving downstream along the upper surface as shown, and asmall region of such air flow aft of the leading edge is obtained.

vPressures immediately aft of this shock, in the subsonic portion of theflow are greater than before spill-over occurred, owing to thedeceleration of the flow in this region. 7 However, these pressures arestill considerably less than those obtained along the lower surfaces in.This pressure force differential between the upper and lower surfaces ofthe airfoi acts to force the airfoil away from lower Wall 3. The sameeffects will occur as the airfoil approaches upper wall 2, except thatthe forces Will be oppositely applied. Thus, as the airfoil approacheseither wall the described aerodynamic effects obtain and a stableposition of the airfoil, out of contact with both walls, is maintained.

The effects of turning moments due to the pressure distribution over theairfoil will affect the angle of attack of the airfoil to some degree,depending upon the design of the airfoil, and upon the torsional andfiexural rigidity of the airfoil and its supporting structure. Thesupport structure design may be varied, depending upon thecharacteristics desired for a particular application, to give a neutralmoment or a slight stalling or a diving moment. A slight stallingmoment, for instance, if applied to the system when spill-over isobtained, results in an increased angle of attack of the airfoil chordline to the relative wind and even greater pressure differentials overthe airfoil than before.

The chart of FIG; 4 gives an approximation of the supersonic trackfollower-guide wall combination design characteristics. M is hereinplotted against h'/ c, where h, as seen in FIG. 3, represents thepassage width between configuration, 2) acceptable passage widths whenchord and speed are known, or (3) the chord, when passage width andspeed are known. As an example, assume that .an airfoil having a twofoot chord is to be operated at a speed of M=2.5. it will be noted for M=2.5 that the h/c value between the lines runs from 0.4-8 to 0.58. ifthe value selected is 0.58, It may be found by applying the formulah/c=0.58. hf then equals 0.58 2 ft. or

1.16 ft. The maximum thickness of the follower for these calculationshas been assumed as i/c=.05. For the 2 ft. chord represented above thethickness (I) would 7 then be .10 ft.

The above analysis has dealt only with a two-dimensional follower. Theinventive principle described, however, may be extended tothree-dimensional practical applications, wherein certain advantagesexist. Here, the pressure buildup prior to spill-over is more gradualthan in the two-dimensional case. The bow shock actually formsrearwardly of the follower leading edge and since a portion of the airmass building up rearwardly of the shock tends to slip around the sidesof the follower the bow shock moves forward gradually. There are nosudden changes in aerodynamic characteristics, hence operationalstability is greater and control is easier. Numerous applicationsutilizing the inventive principle are possible and several variationsare hereinafter described.

FIG. 5 serves to illustrate one configuration of this invention appliedas a low friction aerodynamic hearing and is of a type which is used toreplace ball or roller bearings. In FIG. 5 a plurality ofaerodynamically shaped arms 11 are shown radially extending from andfixed to an axially rotatable load-carrying shaft 13. Each extension arm11 has a lower surface 11a and an upper surface lib and is flanked atits outer end by an aerodynamically shaped object. An airfoil 12, inthis case, is shown attached substantially normal to each arm 11. Arms11 are freely rotatable within a flat, circular cavity 1d definedbetween a guide wall 16 adjacently spaced from surfaces Illa and a guidewall 17 adjacently spaced from surfaces lib. A rfoils 12 are likewisefreely rotatably internally of guide wall 18 which forms the peripheryof cavity 14. Outer surfaces 12a of airfoils 12 are adjacent to andspaced from said peripheral guide wall. A rotary force initially actingupon shaft 13 is subsequently transferred to airfoil shaped arms 11 andairfoils l2, driving them supersonically with respect to guide walls to,17 and 18. The aerodynamic effects heretofore described then serve tosupport arms 11 out of physical contact with walls 16 and 1L7 andairfoils 12 out of physical contact with wall 18. Shaft 13 and thestructural load which it carries are thu supported in a virtuallyfriction-free rotational state. Multiple banks of the described bearingmay be used to provide added ability to support weight and to give shaft13 horizontal stability. It is desirable that the cavities in which theaerodynamic shapes of this type of bearing move be confined with aslittle Wall space as possible while still maintaining sufficient wallspace for bearing operability. The resulting open area combatsanytendency for the fluid medium to be accelerated with the aerodynamicshapes. Standard bearing means may be utilized to accept setructuralloads during periods of supersonic bearing inoperability. In the presentinstance a slip ring 19 is rigidly attached to shaft 13 and adapted tobear upon shoulder 20 until the rotational speed of arms llll issufficient to accomplish the aerodynamic sup port of loads appliedthrough shaft 13.

Other follower and guide wall shapes may be utilized in this generaltype of bearing construction if their characteristic shapes facilitatesthe aerodynamic support heretofore described. An ogival shaped followerand a matching guide wall may, for instance, be substituted for air foil12 and guide wall 13 of the FIG. 5 configuration.

FIG. 6 serves to further illustrate the principle of this invention asapplied to an ogival follower surrounded by a tubular guide. An ogivalfollower 21 is herein axially located within a longitudinally extendingtubular track member '24 which has a circular cross section. Tubulartrack 24 is independently and immovably supported through a supportmember 25 and has a slot 26 longitudinally extending along its lowersurface. -A structural load 22, which, for example, may be a vehicle forpassenger or freight transportation, is structurally attached tofollower 21 through a support arm 23. Since track 24 is immovablyretained, follower 21, when moved supersonically relative to a fluidmedium within said track, is aerodynamically supported in the mannerheretofore described. The propulsive force required t0 move folfore notdescribed.

A wear plate 27 may be attached to support armZS I interiorly of tubulartrack 24 and positioned to prevent follower 21 from contacting tubulartrack 24 during subsonic operation or stop. An airfoil 28 may beattached to support arm 23 between track 24 and vehicle 22. This airfoilmay be normally positioned and movable relative to support arm 23 aboutan axis 2% and cotrollable to have a pitching moment.

in operation, when a propulsive force acting on vehicle 22 moves thatvehicle in a direction indicated by arrows 30 the subsonic operationalphase is initiated. Wear plate 27 or a. similar interim support device,is at this time in contact with the internal surface of track 24adjacently of slot 26. As the speed of vehicle 22 and all of thestructure attached thereto increases, airfoil 28 is rotated clockwiseabout axis 29 by a standard controlling mechanism com-prising, forexample, a hydraulic actuating system with a power cylinder and a bellcrank mechanism (not shown). This increases the airfoil angle of attackand a resultant lift of airfoil 23 with respect to the air through whichit is moving is achieved. The airfoil during this operational phase willsupport at least a portion of the structural load thus substantiallyreducing frictional losses by lightening the load which must besupported by tubular track 24 through wear plate 27. When supersonicoperation is achieved, follower 21, operating aerodynamically withintubular track 24, will aerodynamically support the structural load andwear plate 27 will be moved upward out of contact with track 2 Airfoil28 may continue to support part of the load thus taking a portion of thestrain from track 24. During deceleration, when the movable structureslows to subsonic speeds the operational sequence is reversed. It shouldbe understood that any number of the described fo-llower and track mightbe used in cooperation with and in any location with respect to astructural load. The load may, for example, be supported in a horizontalplane between two or more ogival bearings. Support arms 23 would in thiscase extend through a slot on the side rather than the bottom of tubulartrack 24.

FIG. 7 illustrates an aerodynamic support assembly for a supersonioallymovable vehicle in a different application of the inventive principle.Herein two contiguously joined interconnecting troughs 34 containing aliquid 36 are supported by a common support member 35. An airfoil 31having its leading edge directed longitudinally of troughs 34 ispositioned above the liquid surface 37 in each trough. Rigidly attachedto the top of each airfoil 31 and extending around trough 34 in anadjacent spaced relationship is an airfoil section 31a. The aerodynamicprinciple of this invention is then operative during relative movementbetween airfoil section 31a and the adjacent surfaces of trough 34 andbetween airfoil 31 and liquid surface 37. Airfoil 31 and airfoil section31a are arbitrarily shown to be of biconvex cross section in thisembodiment.

The placement in troughs 34- of liquid 36 achieves a highly desirableself-adjusting surface whereby vertical tolerance problems are virtuallyeliminated. it may be desirable in some instances to freeze liquid 36.This in no way destroys the aerodynamic effects during operation. Liquidviscosity may also be varied as desired without detrimental effects.Wear plates 38 or rollers 39, shown alternately on opposite sides oftroughs 34, may be attached internally of airfoil sections 31a forsubsonic operational support.

It can be appreciated that single or multiple troughs may be useddependent upon the particular design characteristics desired forspecific applications.

FIG. 8 illustrates a modification to an existing slipper arrangement fora supersonic sled. A standard railroad rail 44 or a similarlyconstructed track, representing guide surfaces, is used in combination:with track follower 41. Track follower 41 may be of either therectangular cross section illustrated, a substantially oval crosssection to more nearly match the contour of a standard railhead, or

any desired similar shape to conform to the shape of the particular railhead used. Herein it is comprised of a plurality of airfoil sections llncooperatively surrounding head 44a of rail '44. Airfoil sections 41a areintegrally connected at their sides to form a hollow, elongated trackfollower, the follower being split axially by a slot 46 which extendsthrough the center of one of its sections. Each section 41a has anaerodynamically shaped inner surface 41b. Shank 44b of rail to extendingthrough slot 46 in one of the airfoil sections rigidly joins rail head44a to a base portion 44c. A structural support member is rigidlyconnected from follower 41 to a vehicle or load (not shown) to besupported. A conventional slipper or slide means 47, attached tofollower 41 through support 43, surrounds rail head 44a and positionsfollower 41 both vertically and horizontally with respect to rail head44a during subsonic follower operation.

It will be noted that airfoil sections 41 contain in their forwardportions a series of air bleeds. These bleeds may be slots, asillustrated, perforations or similar aperture means and are provided tomake the present invention more stable in operation. During containphases of supersonic operation throat section 49, which is the minimalair passage area as defined between rail head 44a and the point ofmaximum thickness Sil on follower lltends to become choked, oroverloaded, with an excess of air. This choking condition piles up awall of air ahead of throat section 4? and can cause an unstablefollower operation and high drag. Therefore the bleeds 48 have beenprovided so that when the throat chokes and the normal shock wave movesforward of the bleeds and higher pressure subsonic flow exists betweenthe follower and the track at that point, the air excess is allowed tosquirt out through air bleeds 48 to the lower pressure supersonic flowoutside the follower thus relieving choking and allowing the follower toagain achieve a stable operating characteristic.

When the track follower of FIG. 8 is used in an upright position, asshown, it becomes necessary to use a plurality of such followers with aplurality of rails in order that the structural load might be stablysupported.

FIG. 9 illustrates a supersonically movable vehicle 52 supported by aplurality of track followers 51 operable in cooperation with tracks orguides 54. The right side shows a single follower and track While theleft side shows a double arrangement. The followers are made up of afirst airfoil 51a structurally fixed to support arm 55 which isconnected at its opposite end to vehicle 52. A second airfoil 51b isfixedly attached to airfoil 51 at the point of its support armattachment and at approximately a right an le with respect thereto.Track 54 is comprised of two horizon-tally extending, elongated, spacedplates 54a, each plate having a side rail or flange 56 extending atapproximately right angles from its inner edge and away from the flangeon the opposite plate. Airfoil file is located between and spaced fromplates 54a and airfoil 5th is adjacently spaced from the internalsurface of flange as. Supports 53 or other conventional bracing methodsprovide structural support for tracks 54.

At least one follower and guide combination mus-t be employed on eachside of the vehicle 52, otherwise the follower would obviously beallowed to move from; between plates fits and become inoperable.However, when at least one follower is utilized on each side of thevehicle horizontal stability is maintained by the action of aerodynamicforces between airfoils 51b and flanges 56. Any desired number offollowers may be employed along the length of the vehicle or incooperation with each track. Subsonic support means 57 is provided toassure that there will at no time be physical contact between follower51 and track 54. A conventional slipper arrangement is shown herein.

While numerous structural variations, several of which have beendisclosed, might be achieved for carrying out the disclosed principle,it is the new and useful cooperaarouses tion between a supersonicallymovable, aerodynamioally shaped object and adjacently spaced guide meanswhich is represented as being inventive. Although the invention has beendescribed and illustrated in detail, it is clearly understood that thesame is by way of illustration and example only and is not to be takenby way of limitation, the spirit and scope of this invention beinglimited only by the terms of the appended claims.

I claim:

1. A low friction suppont comprising at least one supersonically movableaerodynamic airfoil having a support face immersed in and freelysupported by a fluid medium, guide surfaces situated substantiallyadjacent and substantially parallel to the chord of said airfoil, saidairfoil being in substantially fixed angular relationship with saidguide surfaces, the center portion of said suppont face of said airfoilbeing nearer the adjacent guide surface than the forward end of theairfoil, whereby the airfoil is entirely aerodynamically spaced fromsaid guide surfaces when supersonic movement is established between saidairfoil and said fluid medium.

2. A low friction support comprising the combination of at least onesupersonically movable aerodynamic shape having its maximum thicknessreaiwardly of the front end and being affixed to a structural load, andguide surfaces situated substantially adjacent to and cooperating withsaid shape, said aerodynamic shape having at least one cornsaid guidesurfaces forming a threat section at the rear- Ward end of saidcompression surface, said shape'being in fixed angular relation to saidguide surfaces, whereby said shape is entirely aerodynamically spacedfrom said guide surfaces when moved supersonically relative to a fluidmedium located intermediately around said shape and said surfaces.

3. In combination with a structural load at least one aerodynamicbearing for the su-ppont of said load, said bearing comprising at leastone independently sup-ported guide surface, and at least one airsupported free floating aerodynamically-shaped guide surface followerpositioned adjacently of and in fixed angular relation with said surfaceand being structurally attached to said lead, said follower having aforwardly facing rearwardly extending compression surfacefacing saidguide surface, forming a throat section at the rearward end of saidcompression surface between said compression and guide surfaces, all ofsaid follower being retainable in an adjacently spaced relationship fromsaid surface by aerodynamic forces when said follower is movedsuper-sonically.

. 4. In combination with a vehicle operable at supersonic speeds, meansfor supporting said vehicle, said means comprising a plurality ofimmovably positioned parallel airfoil tracks extending longitudinal y inthe direction the vehicle is'moved and a plurality of airfoil assembliesfixedly attached to and movable with said vehicle, each of said airfoiltracks comprising a first and a second guide, each of said guides havinga longtiudinally extending plate parallel to and spaced from acounterpart upon the other of said guides, longitudinally extending siderails amxed substantially at right angles to each of said plates anddirected away from the other of said plates on the respective track,each of said airfoil assembli s being guidable by said airfoil tracksand comprising an airfoil positioned between and spaced from saidparallel plates and having at least one of its ends extending beyondsaid side rails, flanking airfoils afllxed to said firstmentionedairfoil at approximately right angles and extending substantiallyparallel to said side rails, each of said airfoils having transverseleading and trailing edges longitudinally and laterally movable withrespect to said tracks, said airfoils being formed with a portion oftheir surfaces which face the surfaces of the respective guides and siderails being located nearer the guides and side rails by a, predeterminedfixed distance thereby forming throat sections between the respectivesurfaces, and structural support means upon said airfoil assemblies forattachment to'said vehicle. 7

5. in combination with a vehicle movable at supersonic speeds at leastone longitudinally extending track on each of two sides of said eldcie,each of said tracks being secured in an immovable position by supportmeans attached thereto, said tracks extending parallel to each other,each of said tracks comprising two horizontally disposed, parallel,elongated spaced plates and a wall attached at right angles to saidplates and co-extensive therewith, at least one track follower attachedto each of said sides of said vehicle, each of said follower beingoperable in cooperation with a diflerent one of said tracksrespectively, each of said track followers comprisa first biconvexairfoil movable in a spaced relationship between the respective parallelplates and having a lea r g edge movable longitudinally of said plates,and a second airfoil rigidly fixed to and movable with said firstairfoil in a parallel and spaced relationship with respect to said wall.

6. In combination, a body member and support means therefore comprising:guide wall means; said body member being adjacent to said guide means;fluid means intermediate said guide wall means md said body memberadapted to move supersonically relative to said body member; surfacemeans on said body member constructed and arranged to face and cooperatewith said guide means for maintaining all of said body member apredetermined distance from said guide means when said fluid means ismoved supersonically relative to said body member.

7. In combination, a body member and support means therefore situated inan aerodynamic environment comprising: stationary guide means; said bodymember being adjacent to said guide means; surface means on said bodymember cooperating with said guide means for urging all of said bodymember a predetermined distance away from said guide means when saidbody member moves supersonically relative to said guide means.

8 In combination, a body member and support means therefore comprising:guide means; said body member being adjacent to said guide means;surface means formed on said body member constructed and arranged toface said guide means for maintaining all of said body memher out ofcontact with said guide means when said body member is movedsupersonically relative to a fluid environment therearound, a foreportion of said. surface means constructed and arranged to be a firstpredetermined distance from said guide means, an aft portion of saidsurface means constructed and arranged tobe a second predetermineddistance from said guide means, greater than said first predetermineddistance, whereby pressure differentials created in said fluidenvironment are operative to maintain said body member out of contactwith respect to said guide means during relative supersonic movements ofsaid body member.

the direction said body member is moved, said body member constructedand arranged adjacent to said support means and having airfoil meansthereon, facing said airfoil track for guiding and urging all of saidbody member a predetermined distance away from said airfoil track whensaid body member moves supersonically relative to said support means,said support means further comprising guide track means formed thereinfor cooperating with bearing guide means formed on said body memberadjacent to said guide track means for guiding said body member relativeto said support means during relative subsonic movements.

11. A track and follower comprising: elongated stationary guide meanshaving first and second guide portions mutually from each other spacedby an amount 11, an airframe immersed in fluid and aerodynamicallysupported between said portions for motion relative to the guide meansand fluid at supersonic speed, said airframe having a chord length c anda thickness t, said airframe and guide means being proportioned for agiven Mach number M and a selected ratio of t/c to provide a ratio ofh'/c not less than the value h/c corresponding to said given Mach numberof the graph of FIG. 4, whereby the airframe is aerodynamically stableand entirely supported aerodynamically at speeds above said Mach number.12. In combination, a pair of track and follower assemblies eachcomprising:

elongated stationary guide means having first and second guide portionsmutually spaced from each other by an amount it, an airframe immersed influid and aerodynamic-ally supported between said portions for motionrelative to the guide means and fluid at supersonic speed, said airframehaving a chord length c and a thickness 1,

said airframe and guide means being proportioned for a given Mach numberM and a selected ratio of t/c to provide a ratio of Iz'/c not less thanthe value h'/c corresponding to said given Mach number of the graph ofFIG. 4, whereby the airframe is aerodynamically stable and entirelysupported aerodynamically at speeds above said Mach number;

said guide means being spaced from each other,

a vehicle supported from the airframe in each said guide 1111621115 andlocated externally of said guide means.

13. The combination of claim 12 wherein at least one of said "assembliesincludes a second airframe fixed to said first mentioned airframe andoriented at right angles thereto,

said guide means having normal guide portions fixed to said firstmentioned portions and extending at right angles thereto in contiguitywith said second airframe.

References Cited in the file of this patent UNITED STATES Pr TENTS2,296,771: Crawford Sept. 22, 1942 2,511,979 Goddard June 20, 19502,724,966 Northrop Nov. 29, 1955 3,006,288 Brown Oct. 31, 1961 FOREIGNPATENTS 168,415 Austria Sept. 25, 1951

4. IN COMBINATION WITH A VEHICLE OPERABLE AT SUPERSONIC SPEEDS, MEANSFOR SUPPORTING SAID VEHICLE, SAID MEANS COMPRISING A PLURALITY OFIMMOVABLY POSITIONED PARALLEL AIRFOIL TRACKS EXTENDING LONGITUDINALLY INTHE DIRECTION THE VEHICLE IS MOVED AND A PLURALITY OF AIRFOIL ASSEMBLIESFIXEDLY ATTACHED TO AND MOVABLE WITH SAID VEHICLE, EACH OF SAID AIRFOILTRACKS COMPRISING A FIRST AND A SECOND GUIDE, EACH OF SAID GUIDES HAVINGA LONGITUDINALLY EXTENDING PLATE PARALLEL TO AND SPACED FROM ACOUNTERPART UPON THE OTHER OF SAID GUIDES, LONGITUDINALLY EXTENDING SIDERAILS AFFIXED SUBSTANTIALLY AT RIGHT ANGLES TO EACH OF SAID PLATES ANDDIRECTED AWAY FROM THE OTHER OF SAID PLATES ON THE RESPECTIVE TRACK,EACH OF SAID AIRFOIL ASSEMBLIES BEING GUIDABLE BY SAID AIRFOIL TRACKSAND COMPRISING AN AIRFOIL POSITIONED BETWEEN AND SPACED FROM SAIDPARALLEL PLATES AND HAVING AT LEAST ONE OF ITS ENDS EXTENDING BEYONDSAID SIDE RAILS, FLANKING AIRFOILS AFFIXED TO SAID FIRSTMENTIONEDAIRFOIL AT APPROXIMATELY RIGHT ANGLES AND EXTENDING SUBSTANTIALLYPARALLEL TO SAID SIDE RAILS, EACH OF SAID AIRFOILS HAVING TRANSVERSELEADING AND TRAILING EDGES LONGITUDINALLY AND LATERALLY MOVABLE WITHRESPECT TO SAID TRACKS, SAID AIRFOILS BEING FORMED WITH A PORTION OFTHEIR SURFACES WHICH FACE THE SURFACES OF THE RESPECTIVE GUIDES AND SIDERAILS BEING LOCATED NEARER THE GUIDES AND SIDE RAILS BY A PREDETERMINEDFIXED DISTANCE THEREBY FORMING THROAT SECTIONS BETWEEN THE RESPECTIVESURFACES, AND STRUCTURAL SUPPORT MEANS UPON SAID AIRFOIL ASSEMBLIES FORATTACHMENT TO SAID VEHICLE.